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F. SCHOENWOLF AND R. l. UTTER.

TELEPHONE SYSTEM.

APPLICATION FILED MAR. 20. m5.

Patented Oct. 7, 1919.

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FRED SCHOENWOLF, OF CHICAGO, AND RICHARD I. UTTEB, OF OAK PARK,ILLINOIS, ASSIGNORS TO KELLOGG SWITCI-IBOARD AND SUPPLY COMPANY, OFCHICAGO,

ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Oct. '7, 1919.

Application filed March 20, 1915. Serial No. 15,862.

To all whom it may concern:

Be it known that we, FRED SCHOENWOLF and RICHARD I. Um, citizens of theUnited States of America, residents of Chicago and Oak Park,respectively, county of Cook, and State of Illinois, have inventedcertain new and useful Improvements in Telephone Systems, of which thefollowing is a specification.

Our invention relates to telephone systems and has to do moreparticularly with service meter apparatus associated with manual linkcircuits and has forits object the provision of a new and improvedsystem of the above character. 7

One of the features of our invention is the provision of improved meansfor actuating a service meter, associated with an operators position,once for each original call and for each recall. Another object of ourinvention is the provision of improved means for preventing conversationbetween a calling and a called subscriber until the operator hasproperly assessed toll against either the called or calling subscriber.A further object of our invention is the provision of supervisory meansfor signaling an operator when to assess toll and to notify her whetherthe answering and the calling terminals of the cord circuit areoperatively associated so that conversation may be carried on betweenthe calling and the called subscribers. These and other features of ourinvention will be moreparticularly pointed out in the specification andclaims.

For a better understanding of our invention reference may be had to theaccompanying drawing in which a calling substation A and a calledsubstation B are shown, being of the well-known common battery type,terminating at the exchange in the line circuits L and L respectively.

The line circuit L comprises a line relay LR, a cut-off relay CO, a linesignal S, and the multiple jacks J. The substation B is similar to thesubstation A except that party line terminals B, B and B are shown. Theline circuit L to the right of the drawing is similar to L, bearing thesame reference characters but having thesufiix prime added. Associatedwith the substation equipment A is a coin collecting device CC. Thisdevice may be of any of the well-known types of pay stations in which isprovided a plurality of coin chutes or slots of different sizes adaptedto receive coins or tokens of different denominations. The mechanism isarranged in such a manner that when a coin is deposited in one of thecoin chutes an audible signal is caused to be transmitted to theoperator at the central ofiice to notify her of the denomination of thecoin deposited.

Coin collecting devices of this character are well-known in the art andtherefore it is thought unnecessary to go into detail as to theconstruction of the same, as our invention is not to be limited to anyone specific type of pay station for it is obvious that marciy differenttypes of paystations may be use The operators cord circuit 0 comprisesthe usual answering plug AP and the calling plug OP, the two plugs beingconnected by the heavily marked tip and sleeve conductors and having thecondensers K and K interposed. At the answering end of the cord circuitis provided a tip answering supervisory relay AT and a sleeve answeringrelay AS, the two relays controlling the answering supervisory lamp AL.A link disconnect relayLD is also provided so that a calling subscribermay recall as soon as his receiver has been replaced prior to theremoval of the answering plug AP from the jack of his line. Thereplacing of the receiver energizes the relay LD thereby disassociatingthe subscribers line circuit from the answering plug of the cord circuitso that the subsequent removal of the subscribers receiver will againcause the line lamp S to glow to notify the operator that the subscriberwishes to recall.

A service meter circuit SM which is common to an operators position isassociated with the answering ends of the cord circuits, and comprises ameter relay MR controlled by the relays AS and AT, a locking relay LOwhich is energized upon the actuation of the relay MR- and the metermagnet MM controlled by the locking relay L0. The meter magnet MMdirectly controls the counting mechanism of the meter registeringdevice.

In connection with the calling end of the cord circuit C is provided acalling sleeve tomatic listening and disconnect of'the 0peratorstelephone set .0 is also provided. The operators set 0 which is commonto a plurality of cord circuits, is adapted to be connected'to the cordcircuit C through contacts of the relay AS when connection is made witha calling line, and disconnected by the operation of the relay CS whenconnection is extended to a called line.

A two-way key is also provided including the recall and answeringcontacts RA, andlink connecting contacts'CK. The key 1s adapted whenthrown in one direction to close the contacts RA and when thrown in theopposite directionto close the contacts CK. The operation of these twosets of contacts will be more fully described in th'e'ensuingspecification. 7 A second operators listening key LK is provided forconnecting the opcratorsset Oto the calling end of the cord circuit. Alink control relay LC is also associated With the calling'end of thecord circuit and is operated upon response of the called subscriber tolight the link control lamp LT. The lighting of this lamp notifies theoperator that the link connecting contacts CK have not been operated toconnect the subscribers in conversational circuit. The operation of thesaid contacts also opensthe circuit of the relay LC to ef= face thesignal LI. "Should the calling subscriber be a pay-station,-asillustrated at A, the lamp LT also serves the purpose of notifying theoperator that she has not thrown thetWo-way key to close the contacts BAto request the subscriber to'deposit the coin or token in the coinapparatus at the sub station. 7

Having described in general theapparatus embodied in the preferred formof our invention,- we Will now describe in detail,

the operation otthe apparatus used in con-' necting a subscriber at thecalling substation A to a subscriber at the called substation B.

Assuming now that the subscriber at substation A initiates a call, theremoval of the receiver thereat operates the line relay LR to bringabout the lighting of theline signal S. The. operator noting the lightedline signal S inserts the answering plug AP into the multiple jack J ofthe calling line. The insertion of the plug AP into the jack Jestablishes a series energizing circuit for the answering supervisoryrelay AS or" the cord sleeve contacts of the connected plug and 7 jack,through the winding of the cut-ofl' relay CO to ground. The energizingof the cut-oii relay CO opens the circuit of the line relay LE to effacethe line signal S. i

The energizing' of the relay AS of the cord circuit C connects theoperators set 0 through the alternate contacts 2 and 30f the relay AS,the'norinal contacts at and 5 of the relayCS to the answering end of thecord circuit C, thus placing the operators set 0 in conversationalcircuit with the calling subscriber.v The answering tip supervisoryrelay AT is also operated upon the insertion of the plug AP into thejack J.

The circuit for relay AT extends from bat-' tery through the winding ofrelay AS, contact 1 of relay LD, sleeve contacts of plug AP and'jack J,to and through the substation, through the tip contacts of jack J andplug P, contact 39 of relay Li) and through the upper Winding of therelay AT 'to ground. 'Thefoperation of the relayAT prevents the'answerng supervisory lamp AL from glowing. An" energizing circuit for themeterrelay MR oft-he service meter circuit SM is also estab'lished'uponthe enter gization or" the re1ay1AS,'the circuit being traced frombattery through the winding of the relay AS, conductor 6, normal contact5 1 of relay CS, the alternatecontact '8 of relay AS, conductor 7through the winding of the relay MR, conductor 8, alternate contact 9 ofrelay AT, alteri'iate contact 10 of relay AS and conductor 11. to groundat normal contact 12 of relay CS Upon the energization of the relayMR'an energizing circuit for-the locking relay L0 is established, tracedfrom battery through the'winding of the relay L0 to ground at alternatecontact 13 of relay The "relay LO then closes v a locklng circuit foritself, traced from battery through the Winding of said relay,

through "its alternate contact 14, resistance 15, conductor 16,alternate contact 2, normal contact 4, conductor 17 and through theupper Winding of the relay-AT to ground.

Upon the initial energization of the relay LO, an energizing circuit forthe meter magnet IVlM is established, traced from battery throughthe'winding-of the said magnet to ground at alternate contact 18 ofthe-relay L0; The magnet MM energizes and at tracts its armature whichoperates the meter mechanism to register the connection set up by theoperator in answering the call from the calling substation. Theoperators set 0 having been'connected upon the energization of relay AS,she now ascerta'ins'the V Wants of the calling subscriber, and assum- COof the line circuit L traced from battery through the winding of therelay CS, sleeve contacts of the connected plug and jack through thewinding of the relay CO to ground, thus energizing the two relays inseries.

Upon the energization of the relay CS, the normal contacts 4t and 5 areinterrupted to automatically disconnect the operators telephone set fromthe cord circuit; The normal contact 4 being interrupted opens thelockin circuit for the relay LO, allowing the said relay to deenergizeand as the service meter circuit SM is common to the position it placesthe meter circuit in condition to register the next call that may be setup by the operator at this position. The closing of the alternatecont-act 12 of the relay CS establishes a circuit for the callingsupervisory lamp CL traced from battery through the said lamp, normalcontact 21 of relay CT to ground at alternate contact 12 causing thesaid lamp to remain glowing until the called subscriber answers. Theoperator now actuates the proper ringing plunger of the ringing ey RK toconnect the proper generator frequency to ring the call bell of thecalled substation, upon the actuation of the said key plunger to itsfully depressed position, the end spring 20 assumes its alternateposition closing an energizing circuit for the ringing control relay RD,traced from battery through the winding of the said relay, the closedcontact 20 of the end spring, normal contact 21 of relay CT to ground atalternate contact 12 of the relay CS. The operator releasing the ringingplunger permits it to assume an intermediate position and allows thecontact springs 20 to return to normal. The relay RD, however, uponenergizing,

, establishes a locking circuit for itself, traced from battery throughthe winding of said relay, conductor 22, normal contact 28 of relay LD,conductor 24, alternate contact 25 of relay RD, and normal contact 21 01relay CT to ground at alternate contact 12 of relay CS. Upon theenergization of the re lay RD, an energizing circuit for the ringinginterrupter circuit R1 is established,

traced fronrbattery through the interrupter I and through the winding ofthe relay RI to ground at alternate contact 26 of relay The ringinginterrupter relay ET is thus lntermittently energized and deenerglzedthrough the medium of the interrupter I, toconnect the ringing lead 27to the tip strand of the cord circuit through the alternate contact 28of the relay R1 to ring the call bell at the called substation. The pathfor the ringing current eXtends from the ungrounded pole of thegenerator, through the alternate contact 28 of relay R1, the alternatecontact 29 of relay CS, the tip contacts of the connected plug and jack,through the condenser and call bell of the called substation, the sleevecontacts of the plug and jack, the alternate contact dO of the relay RD,and through the lower winding 31 of the relay AT through battery toground. The call bell at the calling substation is thus intermittentlyrung until the subscriber thereat answers. The. winding 81 of the relayAT is or" few turns, preferably of German silver wire so that theringing current passing through it induces sufiicient current in theupper 'winding of the said relay AT to give the calling subscriber anaudible signal to notify him that thecalled subscriber is beingsignaled. The called subscriber at the substation B in response to thecall signal removes his receiver from its switch-hook, this act on hispart closes an energizing circuit for the calling tip supervisory relayCT, traced from ground through the winding of the relay CT, normalcontact 28 of relay RI, alternate contact 29 of relay CS, tip contactsof the connected plug and jack, through the substation, the sleevecontacts of the connected plug and jack through the winding of the relayCS to battery. The relay CT, upon energization, opens its normal contact21 efiacing the calling supervisory lamp CL, C

the efiacement of this signal notifies the operator that the calledsubscriber at substation B has answered. The opening of the normalcontact 21 also opens the looking circuit of relay RD which relay upondeie'nergizing opens the circuit of relay RI at contact 26. A furtherresult due to the energization ofthe relay CT is the closing of acircuit through the link control relay LC, traced from battery throughthe winding of the relay LC, the normal contact 32 of the linkconnecting contacts CK the alternate contact 21 of the relay CT, toground at alternate cont-act 12 of relay CS. The relay-LC thereuponenergizes and closes a circuit for the link control lamp LI, traced frombattery through the lamp to ground at alternate contact 33 of relay LC,thus lighting the link control lamp L1. The said lighted lamp serves twopurposes, it notifies the operator that she has not operated the keycontrolling the connecting con tacts CK to place the calling and calledsubscribers in a conversational circuit, and also that she has notassessedtoll against the calling subscriber at the substation A. The

operator then 'actuates the key LK to bridge her set 0 to the callingend of the cord circuit and she now ascertains the number of the calledsubscriber, and noting that it is the same number as'is being called,the operator throws the two-way key to close the contacts BA to connecther set 0 with the answering end of the cord circuit and then notifiesthesubsc riber at the substation A to deposit the'required token in thecoin col lecting apparatus CC. After the calling subscriber at thesubstation A has deposited the proper coin or token,'the operator actu-V ished conversation, they replace their re ceivers upon theirrespective switch-hooks. The replacing of the receiver at the calledsubstation B opens the energizing circuit of the relay CT, allowing itto restore to normaland again light the calling supervisory lamp CL. Thereplacing of the receiver at the substation A opens the energizingcircuit of the relay AT allowing it to restore and again light theanswering supervisorylamp AL. A further result due to thede'e'nergization'of relay AT is "the closing of an energizing circuitfor the link disconnect relay LD. This circuit extends from batterythrough the said relay LD, contact 38 of key springs RA, normal con tact36 of relay AT, alternate contact 37- of relay AS and alternate contact12 of relay OS to ground. The relay LD, upon energizing, opens thecircuit of relay CO at normal contact 1, closes a locking circuit forthe relay AS and disassociates the calling line from the cord circuit.The looking circuit for the relay AS extends from battery through thesaid relay, alternate contact 1 of relay upon deenergizing, restores theline cir- .cuit ofthe calling subscriber to normal to permit thesubscriber to recall.

Should the calling subscriber wish to re call'prior to the time of theremoval of the answering plug from the jack of the calling subscriber,he maydo so by simply removing his receiver and causing the line 7 relayLE .to' cause the'line lamp S to glow as hereinbefore described. Theoperator LD, alternate contact 37 of relay AS and the alternate contact1270f relay OS to ground. The relay CO,

immediately seizes the re'call by throwing Y the two-way key to j closethe contacts BA to bridgeher set O'to the cord f'circuit' to inquire the"wants of; the recalling subscriber. The operation of the contacts RA ofthe two-Way key brings.- about the ppe'ning of the" normal-contact '38.The opening of the normal contact 138 interrupts the circuit ofthe'relay' LD allovving'it to iestore, to

normal .to close its normal contacts "39 and 40 thereby op erativelyconnecting the strands of the cord jcircuit; to'the "line"circl'iit fofthe-recallingsubscriber. "On'a" recall the service meter: registers when5 the calling plug OP is removed"from themultiple jack with which it hasremained connected from the'previous call Upon the removal of thecalling plug GP, the calling supervisory relay CS restores tonormal,allowing the alternate contact 12 to assume 'itsfnor'mal positionthereby closing-theenergizing circuit for'the meter "relay MRv tracedfrombattery through the iwinding of relay AS,

alternate contact 5' of relay CS, alternate contact 3 of relay 'AS,conductor 7 winding of relay MR, "coridu'ctorfl, alternate contact 9 ofr'e'layfAT, alternate oontact'lO of relav'AS and conductor 11"to'groundat nor mal contact'l2. The meter. mechanism is 7 again operated as'hereinb'eforedescribed,

thus giving the operator credit {for "a con- DQCUGHOII' a recall. Theoperator then learns the desires of the recall ng subscriber andcompletes the connection in'the'sam'e manner a hereinbefore described.

In case a calling subscriber asks to'have the charges reversed, that isto have the toll assessed against" the called sub'scriber,

theioperator may'do so, when she operates the listening keyLK to connecther set 0 to 'the, calling end of the cord circuit, in thc same mannerasshe "did when she assessed toll against thecalling subscriber.

The relay L0 is of compar-atively. high resistance as is"also' theresistance ,coil 15, thus when the said relay LO locks up thrtiugh theupper winding -of-tl 1e"relay AT to ground, as before described, shouldthe sub- 7 scriberatthe' calling substation-replace his receiver beforethe connectionto the called substation "is complete d,""the combined resistance of thisfp'ath. is ."such as to allow the relay at AT tode'energize, so as to. place the connected cord circuit; available forother connections. 'I have arranged 1 the circuit of the servi'ce'meterso that. an operator cannot fraudulently operate the same by touchingthe :tip of the" answering plug; 7

AP of one cord circuit" to the sleeve of a plug associated with anothercord circuit.

she attempts to do so only'thefanswering'tip supervisory" relay AT "willbe ope'rated and as the: energizing circuit .for

v the meter magnet MR is open at'the contact 10 of the answering sleevesupervisory relay AS, the said meter relay MR is pre vented fromoperating and remains at normal to prevent the operation of the saidmeter registering device.

Although we have chosen a preferred embodiment for the purpose ofillustrating' our invention, we contemplate using it in other ways thanthat shown and therefore we do not desire to be limited to the exactstructure as described and shown, but aim to cover all that which comeswithin the spirit and scope of the appended claims.

Having described our invention, what we claim as new and desire tosecure by United States Letters Patent, is:

1. A telephone system including subscribers telephone lines, a linkcircuit provided with a pair of normally disconnected terminals forinterconnecting said lines, an operators key for uniting and disunitingthe terminals of said link circuit, a supervisory signal indicating theposition of said key, an operator telephone set, and means forconnecting said operators telephone set to one of said subscriberstelephone lines while said operators key is in normal posi tiondisuniting the terminals of the link circuit. p 2. A telephone systemincluding a calling and a called subscribers line, a link circuitprovided with a pair of normally disunited terminal plugs for connectingsaid lines together, a supervisory signal indicating the response of thecalled subscribed, and means including a key switch for uniting saidnormally disunited terminal plugs and for effacing said supervisorysignal.

3. telephone system including subscribers telephone lines, a linkcircuit provided with normally disconnected terminals forinterconnecting said lines, an operators telephone set, automatic meansfor connecting and disconnecting said operators telephone set and saidlink circuit, and key controlled contacts for connecting said operatorsset to either terminal of the said link circuit to' exclusion of theother end.

A telephone system including subscribers telephone lines, a link circuitprovided with a pair of normally disunited terminal for interconnectingsaid lines, an operators key for uniting the terminals of said linkcircuit, a supervisory signal for indicating the position of saidoperators key, an operators telephone, and automatic means forconnecting said operators telephone to said link circuit.

5. A telephone system including a calling and a called subscribers line,a link circuit provided with a pair of normally disunited terminals forconnecting said lines in conversational circuit, a supervisory signal,means controlled by the response cf the the automatic means controlledby a connected one of said subscribers for disunitin'g the terminals ofsaid link circuit, and operator controlled means for restoring saidautomatic means to normal.

7'. A telephone system including acalling and a called subscribers line,a link circuit for connecting said lines, an operators telephone,automatic means for connecting and disconnecting said operatorstelephone and said link circuit, manually controlled key contact springsfor connecting said operators telephone to either terminal of said linkcircuit to the exclusion of the other terminal, and automatic means fordisconnecting said subscribers lines.

8. A telephone system including subscribers telephone lines, a linkcircuit provided with a pair of terminals for interconnecting saidtelephone lines, an operators telephone, automatic means for connectingand disconnecting said operators telephone and said link circuit,operator controlled key contacts for connecting said operators telephoneto either terminal of said link circuit to the exclusion of the other,and subscriber controlled means for disuniting the terminals of saidlink circuit. i

9. A telephone system including a called subsoribers telephone line anda calling subscribers telephone line, a link circuit pro.- vided with apair of normally disunited terminals for connecting said lines inconversational circuit, a supervisory signal, means controlled by one ofsaid subscribers for op erating said supervisory signal, and operatorcontrolled means for uniting said normally disunited terminals and forefiacing said signal.

10. A telephone system including a calling su bscribers telephone lineand a called subscribers telephone line, a link circuit provided withnormally disunited terminals for connecting said lines in conversationalcircuit, supervisory signals for said link circuit under the control ofthe calling and called subscribers, an auxiliary supervisory signaladapted to be operated by one of said subscribers, and operatorcontrolled means for uniting said normally disunited terminals and forcontrolling said last supervisory signal.

11. A telephone system including a calling and a called subscribersline, a link circuit provided with a pair of normally disunitedterminals for connecting said lines in corn versational' circuit, ananswering supervisory Signal =.under thefcontrol'of the callingsubscriber, a callin supervisory 7 signal under the 00 112101: iofjthecalledlsubscriber,- a, third supervisiory. signal responsive to acontrol exercised fiat ,thej, called substation, operat"contliollfedflmcans,,for unitlng s'ald 119D disunitedfterm-inals andifor efiacing saiclithirdl supervisory signal;

' lvA1te1ephbne systeiniiielnding ,su'b criben s telephone link,circuit, providedjwithfa' pairwof normally disconnected teiniiials'.forconnectinggsaidtelephonelines,

an operator "controlled 'key for. connectingsaid t m na h y om l ting.the @011- ne ion-between.saidlines, anhop erators telep e,v,mea-ns forconnectingsaid. .op'eratorls tel hone tQgBllliBI of ,sa dljsuhscrlbersftele:

phon nes at the-vtimerwhen the terminals of the saidl'linlc circuit aredisconnected, and

' anto inatigc means controlled by one of said suhscribers foli breakingthe; connect i'(' n beT tween sa d fsnbjscmbcrs? lines. V

. 13; Altelephonesy'stem including a calling subscriloers telephone -.1ine andfa calledisubscrihers telephone line, a linkuc rcuitprovidedjwithlafpair of normally disassociated terminals ;forc'onnecting,..sa-id lines, an operatorlcontrollfcd, Key forassoeiatii'ig, said terminals thereby; connecting.saidflines inconve'rsational circuit; asuperviso-ry v signal for circuitfadaptedto-beactuated When the'call'eid isuh'scri-b'er responds, a circuit forsaidsnpenyisory signal, adapted to beopened henj sai'dbperatorrcontrolled means is actu- V ate'dftojjconnje'ct said linesinconversational circuit, and a relay 'under. subStationlcontrol foragain disassociating the terminals of said link-circuit:

14.? A telephone system in-clnding a-call'ing snbscribcfff telephoncline, and ac. called 1 subscriberlstelphoneline, a linkzcircuit forconnecting isaidglines.in ,convensational ,cireu1t,f anjfoperatorls;telephone, automatlc means for connecting and disconnecting saidoperators telephone and sald link uClIOlllll,

' operator controlled contacts foia connecting 7 said operatofistelephoneto the calling sub- 'scribers line to the'exclusionhof thecalled subscriber; and operator controlled contacts forconnecting saidoperators telephone-to the called subscriber liner to the exclusionoffthe calling subscriher. V w 157.. A telephone system. including acalling subscriberstelephone line andfa called suh scrib'ers telephoneline,,: a .link circuit pro-' vided .With a pair; of normally;disconnected terminals for connecting g said lines, an operaton stelephone set, means forrconnecting said operators telephone s et'tosaidcalling subscrihers line, means for signaling" the calledijsubscriber,and an openatori-oonhrolledkey operable thereafter to associate,saiditerminals'TtQ connect said-subscribers line'sin conversationalcircu it 16; A telephone system including, a. calling su-bscribersltelephonefline! and al-c alled subscriberfs telephoneline, alinkwcircuitpro- V vided with ;a pair Q of .normally.disassociated terminals ;forconnecting said-lines, an op erators telephone set; means for,connecting the operators telephone set mend, calling subscribers line, asupervisory signal, means controlled, by v the: called subscribe or. a

tuating said SIlPBIZVlSOIYSlgLlELL andfan open five cents each byaddressing-the fOOminiS SiOneI of lPatents,

